Implantable cardioverter-defibrillators are known in the art. Prior devices have included transvenous devices that include leads that reside in blood vessels and electrodes placed in or on the heart, or epicardial devices that include electrodes placed on the outside of the heart. Newer alternatives may include subcutaneous-only systems which lack leads in or on the heart. One challenge in designing any implantable system is the proper handling of signals if/when input circuitry becomes saturated due to internal or external electrical events.